1. Technical Field
The present invention relates generally to graphical/textual user interfaces, and more specifically, to a method and system for securing machine interface access.
2. Description of the Related Art
Computer systems and dedicated devices such as automated teller machines (ATMs) increasingly provide access to interfaces that must be protected from unauthorized use. Typical security on such user interfaces is provided by a password or “personal identification number” PIN) that must be provided to the user interface via an input device prior to further access by an individual (or in some instances another machine) accessing the interface.
The level of security provided by a “weak” password or token such as a password or PIN is generally related to its length and arbitrariness. However, the same factor is also determinative of the difficulty for a human to remember the token. Also, the number of possible token element values, e.g., just digits versus digits plus letters is generally made larger to improve security, but the input set size increase is generally either thwarted by use of common words or numbers within the total possible space of values.
While it is possible to provide “hints” to a user that will stimulate a recollection of the token, such hints also provide a potential security breach in that the token may be discoverable via guessing once the hint is given. Other systems include a secondary password that has some concrete meaning to the token owner that can be used to reveal the actual token. For example, an interface may use the users mother's maiden name or “favorite animal”, etc. as a secondary token to protect the underlying access token if the user forgets.
Two-dimensional textual or graphical hint systems have been proposed, from systems that actually display the password in a form such as a “hidden word” puzzle to systems that use a randomized arrangement of icons that must be selected in order or a particular arrangement of icons that must be selected in a pattern in order to satisfy token entry. All of the above systems have an advantage in that they are not easily overcome by mere repetitive machine input.
However, all of the above systems may reveal their underlying token eventually through human observation, especially when the underlying token hiding mechanism is known a priori. For example, if it is known that the token hiding mechanism is a particular arrangement of icons that must be selected in a pattern, an observer can ignore the actual icons and merely note the pattern.
A token system having improved “strength” can rely on a smaller set of element input values, can use longer-lived passwords and/or can be used across multiple systems without the same risk of compromise as weaker passwords.
Therefore, it would be desirable to provide a method and system for hiding tokens in a hint display that cannot be easily discovered through observation of token entry patterns and values.